As tempting as it can be to let it all hang loose and stop worrying while on vacation, you do want to be aware of your ecological impact. Without a little planning, you may (31) specific environmental and social issues in a given location. You are also inherently reliant on transportation that may be better or worse (32) greenhouse-gas emissions. The synonym for the eco-savvy traveler is (33) . First of all, you should choose ecologically (34) modes of transportation. This means lessening or eliminating your dependence on travel (35) that result in heavy carbon footprints. Airplanes and cars (36) significant amounts of greenhouse gases to the atmosphere. Walk or bicycle as much as possible—a good method of (37) yourself in your destination. Electric trains and buses are also examples of more efficient and cleaner (38) of mechanized travel. Secondly, investigate the agencies you may choose for your trip to find out their practices and reputations. Ask the company (39) what they do for the local community and (40) they ran their operations. Some may contribute little economically to the area or they may (41) engage in ecologically damaging practices, (42) fuel-costly tours or excessive harassment of wildlife in the name of sightseeing. Thirdly, buy locally. This simple practice can have (43) positive implications, both ecologically and economically. (44) of food and other goods from outside the region (45) a lot of energy in the form of transportation and environmental processing. (46) foods that are regionally in-season and locally produced reduces (47) and helps support local farmers and manufacturers. Finally, tread lightly on the landscape. When visiting a wild area, don’t drive or bicycle off designated routes. If camping, (48) up all garbage or dispose of it in designated receptacles. (49) if dispersed camping is permitted, use preexisting camps (50) possible to lessen erosion.

A. however
B. whenever
C. whichever
D. wherever